Therapy of chronic extensor mechanism deficiency after total knee arthroplasty using a monofilament polypropylene mesh.

Introduction: Lesions of the quadriceps or patellar tendon after total knee arthroplasty (TKA) are a rare but serious complication which, if left untreated, can lead to loss of function of the knee joint. While acute and subacute extensor mechanism disruptions may have several causes, chronic deficiencies are often related to multiple prior revision surgeries for joint infection or aseptic TKA failure. Up to date, biological allograft reconstruction showed unsatisfying results. The use of a monofilament polypropylene mesh is a promising approach for this pathological condition. The aim of the present study was to evaluate clinical, functional and patient reported outcomes of this procedure in patients with chronic extensor mechanism deficiency. Materials and Methods: Twenty-eight patients with chronic extensor mechanism deficiency (quadriceps tendon rupture n = 9, patellar tendon rupture n = 19) after TKA were included in this retrospective study. None of the patients were lost to follow-up. Surgical reconstruction was performed at one institution between 2014 and 2020 with a monofilament polypropylene mesh (Marlex Mesh, Bard, Murray Hill, USA). The mean age at the time of surgery was 69 years. Patients presented with a mean BMI of 33 kg/m2. The mean follow-up period was 23 months. Results: The 2-year survivorship free of mesh revision was 89% [95% confidence interval (CI): 75% to 100%]. Three patients (11%) had to undergo revision because of mechanical mesh failure and received another polypropylene mesh. No further revisions were performed thereafter. Flexion was 87° (range, 30-120°) on average. The majority of patients (75%, 21/28) had a full active extension. The mean active extension lag after surgery was 4 degrees (range, 0-30°). Discussion: We observed a substantial improvement of extensor mechanism function. The majority of patients had full extension and showed good clinical results. A failure rate of over 50% has been published for alternative procedures. Thus, the use of the described augmentation technique represents a reasonable treatment option for chronic extensor mechanism disruptions of the patellar tendon as well as the quadriceps tendon after total knee arthroplasty. However, there might be a potentially higher risk for infection persistence in periprosthetic joint infection cases due to the presence of a foreign material.

Author Correction: Tibio-Femoral Contact Force Distribution is Not the Only Factor Governing Pivot Location after Total Knee Arthroplasty.

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Tibio-Femoral Contact Force Distribution is Not the Only Factor Governing Pivot Location after Total Knee Arthroplasty.

Total knee arthroplasty aims to mimic the natural knee kinematics by optimizing implant geometry, but it is not clear how loading relates to tibio-femoral anterior-posterior translation or internal-external pivoting. We hypothesised that the point of pivot in the transverse plane is governed by the location of the highest axial force. Tibio-femoral loading was measured using an instrumented tibial component in six total knee arthroplasty patients (aged 65-80y, 5-7y post-op) during 5-6 squat repetitions, while knee kinematics were captured using a mobile video-fluoroscope. In the range of congruent tibio-femoral contact the medial femoral condyle remained approximately static while the lateral condyle translated posteriorly by 4.1 mm (median). Beyond the congruent range, the medial and lateral condyle motions both abruptly changed to anterior sliding by 4.6 mm, and 2.6 mm respectively. On average, both the axial loading and pivot position were more medial near extension, and transferred to the lateral side in flexion. However, no consistent relationship between pivoting and load distribution was found across all patients throughout flexion, with R2 values ranging from 0.00 to 0.65. Tibio-femoral kinematics is not related to the load distribution alone: medial loading of the knee does not necessarily imply a medial pivot location.

Mid-Term Survival of Total Knee Arthroplasty in Patients with Posttraumatic Osteoarthritis.

PURPOSE OF THE STUDY There is limited evidence on survival and complication rates in patients after total knee arthroplasty for posttraumatic osteoarthritis. The failure mechanisms leading to revision remain an issue of constant debate. The purpose of this study was to analyze the mid-term survival of primary total knee arthroplasties as well as to evaluate complications and failure mechanisms in patients with posttraumatic knee osteoarthritis. MATERIAL AND METHODS This retrospective study included 79 patients with an average age of 59 years at the time of primary total knee arthroplasty. A functional and radiographic assessment was obtained during outpatient clinical follow-up at 3 and 12 months postoperatively and yearly intervals after that. Survival rates were calculated using Kaplan-Meier analyses. The mean postoperative follow-up was 69 months. RESULTS At 69 month the revision-free survival rate was 88.6%. In nine cases (11.4%) a revision procedure was performed. The leading cause of revision was a periprosthetic infection (n = 6, 66.6%). An age of fewer than 55 years at the time of total knee arthroplasty had a significant influence on implant survival (p = 0.018) with superior survival in favor of the older patient population. At most recent follow-up, a mean Knee Society Score of 82 points and an average Function Score of 77 points were observed. CONCLUSIONS Periprosthetic joint infection is the primary failure mechanism leading to a revision in patients with total knee arthroplasty for posttraumatic osteoarthritis. Apart from the increased infection rate, total knee arthroplasties in patients with posttraumatic osteoarthritis revealed results that were comparable to patients with primary osteoarthritis. Key words:posttraumatic knee osteoarthritis, total knee replacement, survival, complications, revision, outcome.

Microstructural Changes of Tensor Fasciae Latae and Gluteus Medius Muscles Following Total Hip Arthroplasty: A Prospective Trial.

PURPOSE OF THE STUDY Although total hip arthroplasty (THA) is one of the most successful orthopedic operations, the soft tissue trauma towards the periarticular musculature during surgical approaches remains a critical concern. However, the actual microstructural proof of muscle trauma on the level of the myofiber due to the surgical approach has never been claimed. MATERIAL AND METHODS Patients undergoing THA were prospectively enrolled and either operated by a direct lateral (DL) or a anterolateral minimally invasive approach (ALMI). Intraoperatively and at 6 months follow-up a needle biopsy was taken from the gluteus medius muscle and the tensor fasciae latae. Pre- and post-operative fiber diameter and composition, of gluteal medius muscle (GMM) and the tensor fasciae latae muscle (TFLM) were compared in both surgical approaches. RESULTS A total of 19 patients (12 F; 7 M) were included in this study. The average pre-operative fiber diameter or fiber type composition did not differ significantly in the GMM and TFLM, nor did it vary among patients with different approaches. The muscle fiber diameter significantly increased post-operatively in the TFLM, in both, the DL (p = 0.043) and the ALMI (p = 0.043) approach. There was a trend towards more pronounced muscle fiber changes in the DL (TFLM: p = 0.077; GMM: p = 0.150), compared to the ALMI. DISCUSSION AND CONCLUSIONS Our results show microstructural changes to the periarticular musculature following THA by a compensatory hypertrophy of the TFLM and GMM. These adaptions directly next to the surgical trauma were observed in DL and AMLI. Key words: total hip arthroplasty, skeletal muscle, muscle biopsy, iatrogenic trauma, muscle scar.

Mediolateral force distribution at the knee joint shifts across activities and is driven by tibiofemoral alignment.

AIMS: Tibiofemoral alignment is important to determine the rate of progression of osteoarthritis and implant survival after total knee arthroplasty (TKA). Normally, surgeons aim for neutral tibiofemoral alignment following TKA, but this has been questioned in recent years. The aim of this study was to evaluate whether varus or valgus alignment indeed leads to increased medial or lateral tibiofemoral forces during static and dynamic weight-bearing activities. PATIENTS AND METHODS: Tibiofemoral contact forces and moments were measured in nine patients with instrumented knee implants. Medial force ratios were analysed during nine daily activities, including activities with single-limb support (e.g. walking) and double-limb support (e.g. knee bend). Hip-knee-ankle angles in the frontal plane were analysed using full-leg coronal radiographs. RESULTS: The medial force ratio strongly correlated with the tibiofemoral alignment in the static condition of one-legged stance (R² = 0.88) and dynamic single-limb loading (R² = 0.59) with varus malalignment leading to increased medial force ratios of up to 88%. In contrast, the correlation between leg alignment and magnitude of medial compartment force was much less pronounced. A lateral shift of force occurred during activities with double-limb support and higher knee flexion angles. CONCLUSION: The medial force ratio depends on both the tibiofemoral alignment and the nature of the activity involved. It cannot be generalised to a single value. Higher medial ratios during single-limb loading are associated with varus malalignment in TKA. The current trend towards a 'constitutional varus' after joint replacement, in terms of overall tibiofemoral alignment, should be considered carefully with respect to the increased medial force ratio. Cite this article: Bone Joint J 2017;99-B:779-87.

[Quadriceps tendon insufficiency and rupture : Treatment options in total knee arthroplasty]. / Quadrizepssehneninsuffizienzen und -rupturen : Verfahren zur Behandlung in der Knieendoprothetik.

Quadriceps tendon injuries and insufficiencies in total knee arthroplasty are rare, but are followed by a devastating complication that left untreated leads to a complete loss of function of the knee. This review article summarizes the functional anatomy, risk factors, and the prevalence and diagnosis of quadriceps tendon injuries, in addition to the possible management options for partial and complete ruptures. The treatment options are adapted according to the extent of the loss of function (partial, complete) and the duration of the injury (acute vs chronic). Furthermore, the choice of treatment should take into account the quality and availability of primary tissue, the patient's general health, along with their likely functional requirements. Conservative treatment is often justified in partial ruptures with good results. Complete ruptures require surgical intervention and multiple operative techniques are described. Treatment options for acute ruptures include direct primary repair with autogenous or synthetic tissue augmentation. In the case of chronic insufficiency and a lack of soft-tissue surroundings, reconstruction with the aid of a muscle flap or allograft tissue can be considered. All surgical intervention techniques used so far have been fraught with complications and rarely lead to satisfactory results. A new surgical approach to the reconstruction and augmentation of the extensor mechanism consists of the use of a synthetic mesh. The technique is described here in detail.

[Periprosthetic fractures following total hip and knee arthroplasty: Risk factors, epidemiological aspects, diagnostics and classification systems]. / Periprothetische Frakturen nach Hüft- und Knietotalendoprothesenimplantation: Risikofaktoren, epidemiologische Aspekte, Diagnostik und Klassifikationssysteme.

Periprosthetic fractures following hip and knee arthroplasty are potentially severe complications. As a fundament in diagnostic and therapeutic procedures, specific classification systems are necessary to ensure an optimal individualized treatment of these sometimes complicated fractures. This review article summarizes the epidemiological aspects, risk factors and diagnostics of periprosthetic hip and knee fractures. The most frequently used location related fracture classifications systems are explained. In addition, the recently introduced unified classification system (UCS), which is applicable to any location of periprosthetic fractures, is described in detail. Initial studies have shown a reliable applicability of the UCS to periprosthetic hip and knee fractures.

Ceramic on ceramic arthroplasty of the hip: new materials confirm appropriate use in young patients.

The leading indication for revision total hip arthroplasty (THA) remains aseptic loosening owing to wear. The younger, more active patients currently undergoing THA present unprecedented demands on the bearings. Ceramic-on-ceramic (CoC) bearings have consistently shown the lowest rates of wear. The recent advances, especially involving alumina/zirconia composite ceramic, have led to substantial improvements and good results in vitro. Alumina/zirconia composite ceramics are extremely hard, scratch resistant and biocompatible. They offer a low co-efficient of friction and superior lubrication and lower rates of wear compared with other bearings. The major disadvantage is the risk of fracture of the ceramic. The new composite ceramic has reduced the risk of fracture of the femoral head to 0.002%. The risk of fracture of the liner is slightly higher (0.02%). Assuming that the components are introduced without impingement, CoC bearings have major advantages over other bearings. Owing to the superior hardness, they produce less third body wear and are less vulnerable to intra-operative damage. The improved tribology means that CoC bearings are an excellent choice for young, active patients requiring THA.

[Management of extensor mechanism injuries following total knee arthroplasty]. / Verletzungen und Rekonstruktion des Streckapparates nach Knie-TEP.

Extensor mechanism injuries in total knee arthroplasty include disruption of the quadriceps tendon, disruption of the patellar tendon, and/or patellar fractures. While these injuries are rare, they are a devastating complication to manage. This review summarizes the anatomy of the extensor mechanism, risk factors for extensor mechanism injuries, and the prevalence and diagnosis of extensor mechanism injuries. In addition, this review outlines non-operative and operative management options. A new surgical approach for the reconstruction and augmentation of the extensor mechanism with the use of a synthetic mesh is described in detail. In multiple publications and in our own experience this newly developed technique shows promising results.

[Intraoperative Evaluation of Total Knee Arthroplasty: Anatomic and Kinematic Assessment with Trial Components]. / Intraoperative Analyse der Anatomie und Kinematik in der Knieendoprothetik.

The intraoperative use of trial components in total knee arthroplasty (TKA) is of paramount importance to prevent inadequate ligament balance and to achieve optimal position of the definitive components. This review demonstrates an 8-step algorithm to assess the anatomy of the femoral, tibial and patellar component as well as the kinematics of the tibiofemoral and patellofemoral joints. Trial components allow an easy assessment of the anatomic fit of the final implants. Upon the trials insertion, bone coverage and the component overhang should be evaluated. The femoral rotation should be assessed using the transepicondylar axis and for the tibial component rotation assessment, the tibial tuberosity would be the most reliable bony landmark. Addressing the patella, sizing and bone coverage should be thoroughly evaluated. In order to restore physiological kinematics the remnants of the meniscus rim can be used to determine the correct reconstruction of the joint line. A tight extension gap results in limited extension, whereas a tight or unbalanced flexion gap leads to "booking" or "spin-out" of the inlay. The POLO test (pull-out, lift- off) allows an easy assessment of the posterior cruciate ligament tension and the size of the flexion gap as well. To prevent postoperative dislocation and overstuffing, specific tests for correct patellar positioning and tracking support should be performed. The anatomy and kinematics of total knee arthroplasty have to be evaluated by trial components on a routine basis before inserting the final implants in order to identify implant positioning errors and inadequate ligament balance.

[Management of Flexion Contracture in Primary Total Knee Arthroplasty]. / Umgang mit der Beugekontraktur in der primären Knieendoprothetik.

Flexion contracture is a common deformity of the arthritic knee. The present publication describes causes, clinical relevance and surgical technique in the presence of flexion contractures in total knee arthroplasty. Flexion contracture can be attributed to different causes. Basically it is a mismatch between flexion and extension gaps. Moderate and severe deformities have to be corrected by additional surgical interventions. In most cases soft tissue techniques with release of contracted structures, the removal of osteophytes and additional distal femoral bone resection are necessary. The goal of these interventions is to achieve full extension of the knee. During rehabilitation attention has to be paid to maintain it with intensive physical therapy. A remaining flexion contracture is associated with inferior functional outcome and persistent pain.

[A novel technique for a stable intramedullary fixation of static spacers in two-stage septic revision TKA with severe bone defects]. / Technik der stabilen intramedullären Verankerung eines statischen PMMA-Spacers beim zweizeitigen septischen Knie-TEP-Wechsel mit ausgeprägten Knochendefekten.

BACKGROUND: Articulating as well as static PMMA-spacers are routinely used in two-staged septic total knee arthroplasty (TKA) revision surgery. However, if bone defects are excessive and there is substantial instability, conventional spacers without additional stabilisation are inappropriate. Due to the increasing number of multiple revisions and larger bone defects, an absolutely stable spacer construct with appropriate fixation in the remaining bone is required. METHODS: After TKA removal and debridement, AO external fixator steel rods were inserted "press-fit" into the femoral and tibial medullary canal in this technique. Both rods were sealed with bone cement (PMMA) and connected at the joint level in 5° of flexion by an AO external fixator "tube-to-tube" connector. Comparable to a conventional static spacer the joint space is filled with individual antibiotic loaded PMMA. The restoration of the leg axis as well as the distraction of the joint is crucial to preserve the joint space for the second stage TKA reimplantation. Postoperative mobilisation can be conducted under full weight-bearing conditions without external orthosis. CONCLUSION: This technique allows a safe intramedullary fixation of a modified static spacer in septic TKA revision with large bone defects and substantial instability with avoidance of common spacer complications and excellent patient mobilisation.

[Defect Reconstruction in Total Knee Arthroplasty with wedges and blocks]. [Corrected]. / Defektrekonstruktion in der Knieendoprothetik mit Wedges und Blöcken.

OBJECTIVE: Surgical technique for primary and revision total knee arthroplasty to reconstruct bone defects with metal augments and reproducible positioning of the implant at the right joint line. INDICATIONS: Primary and revision total knee arthroplasty with bone defects. CONTRAINDICATIONS: Complete destruction of the metaphysis. SURGICAL TECHNIQUE: Implantation of revision components performed in three consecutive steps: first, positioning of the tibia component at correct height and rotation; second, determination of the posterior joint line in flexion through the size and correct rotation of the femoral implant; third, determination of the distal joint line by use of positioning of the femoral component. These steps are performed independently from bone defects, which are subsequently reconstructed with metal augments. POSTOPERATIVE MANAGEMENT: Mobilization with weight bearing and range of motion as tolerated, depending on osseous and soft tissue condition at primary or revision surgery. RESULTS: In a prospective study, 132 consecutive knee revisions in 76 women and 56 men with an average age of 72.4 years (range 49-93 years) were followed up clinically and radiologically preoperatively and at a mean follow-up of 74 months (range 38-105 months). Clinical results were based on the American Knee Society score. The score was 46.3 (range 31-65) preoperatively and 82.5 (range 61-96) at follow-up. Radiologically 12.1 % of the knees showed lysis around the augment with no clinical signs of loosening. No revisions were performed due to aseptic loosening. The joint line was correctly reconstructed in 84.8 %.

Significant muscle damage after multiple revision total hip replacements through the direct lateral approach.

Intact abductors of the hip play a crucial role in preventing limping and are known to be damaged through the direct lateral approach. The extent of trauma to the abductors after revision total hip replacement (THR) is unknown. The aim of this prospective study was to compare the pre- and post-operative status of the gluteus medius muscle after revision THR. We prospectively compared changes in the muscle and limping in 30 patients who were awaiting aseptic revision THR and 15 patients undergoing primary THR. The direct lateral approach as described by Hardinge was used for all patients. MRI scans of the gluteus medius and functional analyses were recorded pre-operatively and six months post-operatively. The overall mean fatty degeneration of the gluteus medius increased from 35.8% (1.1 to 98.8) pre-operatively to 41% (1.5 to 99.8) after multiple revision THRs (p = 0.03). There was a similar pattern after primary THR, but with considerably less muscle damage (p = 0.001), indicating progressive muscle damage. Despite an increased incidence of a positive Trendelenburg sign following revision surgery (p = 0.03) there was no relationship between the cumulative fatty degeneration in the gluteus medius and a positive Trendelenburg sign (p = 0.26). The changes associated with other surgical approaches to the hip warrant investigation.

[Does the ideal total knee arthroplasty for younger patients exist?]. / Gibt es die ideale Knietotalendoprothese für jüngere Patienten?

BACKGROUND: A total knee arthroplasty (TKA) is still not able to reinstate the physiological kinematics of the knee. This results in a considerable number of unsatisfied patients, especially if they are younger and active. Recently developed TKA systems claim to consider these biomechanical properties. The current study investigates the outcome (range of motion, stability) of the new ATTUNE™ TKA system (DePuy, Warsaw, IN, USA) in in young patients. MATERIAL AND METHODS: This was a prospective study design (55 patients, 55 knees, age < 70 years, 01/2012-07/2012). Patients received an ATTUNE™ TKA and were examined preoperatively and at 6 months postoperatively for range of motion and stability (Knee Society score). RESULTS: Age: 63 ± 8 years; range of motion increased from 112.33 ± 13.6° to 123.60 ± 11,1° (p < 0.001). Coronal stability improved significantly (preoperatively vs. postoperatively, p < 0.001). Sagittal stability was not significantly different (preoperatively vs. postoperatively, p > 0.05). CONCLUSION: The data of this study show improved early functional results in younger patients in comparison to the current literature. However, until now no existing TKA system can be identified as ideal. But taking recent biomechanical knowledge into consideration, modern TKA designs have the potential to improve the functional outcome. Especially for younger patients with superior muscle-status and coordinative abilities this seems beneficial.

[Treatment of Mason type II radial head fractures by percutaneous reduction]. / Die Behandlung von Radiusköpfchenfrakturen Typ Mason II durch perkutane Drahtreposition.

BACKGROUND: The therapeutic algorithm for the treatment of Mason type II radial head fractures is still controversially discussed. This study describes the technique of percutaneous fracture reduction without additional internal fixation of the radial head as an alternative to open reduction and presents the results of the method. MATERIAL AND METHODS: The data from 26 out of 30 patients with a Mason type II radial head fracture who had been consecutively treated with percutaneous fracture reduction were evaluated retrospectively. The analysis comprised the disabilities of shoulder and hand (DASH) score, the Mayo elbow performance score (MEPS) and data from the radiological examinations. RESULTS: The average follow-up time was 21 months (range 6-47 months). In 22 cases (85 %) an anatomical reduction could be achieved, 2 cases (8 %) showed a complete redislocation of the fragment and 2 cases (8 %) a partial redislocation. The average DASH score was 5.6 points (range 0-56) and the average MEPS was 93.8 (range 60-100). Only 4 patients (15 %) reported persisting functional impairment with a DASH score >10. CONCLUSIONS: The method of percutaneous reduction of radial head fractures without additional internal fixation in Mason type II fractures has been demonstrated to be a good alternative to open reduction.

[Complications after minimally invasive total hip arthroplasty]. / Komplikationen nach minimal-invasiver Hüftendoprothetik.

BACKGROUND: The goal of minimally invasive surgery in total hip arthroplasty (MIS-THA) is reduction of surgical trauma without any limitations regarding exposure of the femur and acetabulum to achieve reproducible results. Despite improved instrumentation the implementation of these techniques is associated with a risk of higher complication rates. AIM: The article describes specific and unspecific complications of MIS-THA and gives hints and tips on how to avoid them. MATERIAL AND METHODS: In a retrospective study 152 THA revisions following MIS-THA were examined and an error analysis was performed. RESULTS: The study of 152 MIS-THA revisions included 87 female and 65 male patients. A gender-specific incidence of complications could not be found. The most common indication for revision surgery was due to recurrent dislocation. An increased incidence of fractures of the greater trochanter was observed using the anterolateral approach with the patient in a supine position. DISCUSSION: The MIS-THA procedure contributes to excellent early rehabilitation when performed correctly. The muscle preserving aspect can be counted as an advantage particularly for young patients. This patient collective has a high risk to undergo revision surgery.